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Hydrocarbon contains 18.18% hydrogen and 81.82% carbon. One litre of this gas has the same mass as carbon dioxide. What is the molecular formula of this hydrocarbon?

Answer 1

Natalie Anton

Given the percentage composition of HC as #C->81.82% and H->18.18%#

Thus, the proportion of C to H atoms in its molecule will be

#C:H=81.82/12:18.18/1#

#C:H=6.82:18.18# #=6.82/6.82:18.18/6.82=1:2.66~~3:8#

So the Empirical Formula of hydrocarbon is #C_3H_8#

As the mass of one litre of hydrocarbon is same as that of #CO_2# The molar mass of the HC will be same as that of #CO_2# i.e #44g/"mol"#

Now let Molecular firmula of the HC be #(C_3H_8)_n#

Using molar mass of C and H the molar mass of the HC from its molecular formula is #(3xx12+8xx1)n=44n#

Thus

#44n=44=>n=1#

Hence the molecular formula of HC is #C_3H_8#

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Answer 2

Avery Adams

The molecular formula of the hydrocarbon is C₂H₄, which is ethylene.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.